1 files changed, 173 insertions, 54 deletions

diff --git a/fs/xfs/xfs_exchrange.c b/fs/xfs/xfs_exchrange.c
index c8a655c92c92..0b41bdfecdfb 100644
--- a/fs/xfs/xfs_exchrange.c
+++ b/fs/xfs/xfs_exchrange.c
@@ -72,6 +72,34 @@ xfs_exchrange_estimate(
 	return error;
 }
 
+/*
+ * Check that file2's metadata agree with the snapshot that we took for the
+ * range commit request.
+ *
+ * This should be called after the filesystem has locked /all/ inode metadata
+ * against modification.
+ */
+STATIC int
+xfs_exchrange_check_freshness(
+	const struct xfs_exchrange	*fxr,
+	struct xfs_inode		*ip2)
+{
+	struct inode			*inode2 = VFS_I(ip2);
+	struct timespec64		ctime = inode_get_ctime(inode2);
+	struct timespec64		mtime = inode_get_mtime(inode2);
+
+	trace_xfs_exchrange_freshness(fxr, ip2);
+
+	/* Check that file2 hasn't otherwise been modified. */
+	if (fxr->file2_ino != ip2->i_ino ||
+	    fxr->file2_gen != inode2->i_generation ||
+	    !timespec64_equal(&fxr->file2_ctime, &ctime) ||
+	    !timespec64_equal(&fxr->file2_mtime, &mtime))
+		return -EBUSY;
+
+	return 0;
+}
+
 #define QRETRY_IP1	(0x1)
 #define QRETRY_IP2	(0x2)
 
@@ -91,6 +119,9 @@ xfs_exchrange_reserve_quota(
 	int				ip1_error = 0;
 	int				error;
 
+	ASSERT(!xfs_is_metadir_inode(req->ip1));
+	ASSERT(!xfs_is_metadir_inode(req->ip2));
+
 	/*
 	 * Don't bother with a quota reservation if we're not enforcing them
 	 * or the two inodes have the same dquots.
@@ -189,7 +220,7 @@ xfs_exchrange_mappings(
 	 * length in @fxr are safe to round up.
 	 */
 	if (xfs_inode_has_bigrtalloc(ip2))
-		req.blockcount = xfs_rtb_roundup_rtx(mp, req.blockcount);
+		req.blockcount = xfs_blen_roundup_rtx(mp, req.blockcount);
 
 	error = xfs_exchrange_estimate(&req);
 	if (error)
@@ -298,22 +329,6 @@ out_trans_cancel:
  * successfully but before locks are dropped.
  */
 
-/* Verify that we have security clearance to perform this operation. */
-static int
-xfs_exchange_range_verify_area(
-	struct xfs_exchrange	*fxr)
-{
-	int			ret;
-
-	ret = remap_verify_area(fxr->file1, fxr->file1_offset, fxr->length,
-			true);
-	if (ret)
-		return ret;
-
-	return remap_verify_area(fxr->file2, fxr->file2_offset, fxr->length,
-			true);
-}
-
 /*
  * Performs necessary checks before doing a range exchange, having stabilized
  * mutable inode attributes via i_rwsem.
@@ -324,11 +339,13 @@ xfs_exchange_range_checks(
 	unsigned int		alloc_unit)
 {
 	struct inode		*inode1 = file_inode(fxr->file1);
+	loff_t			size1 = i_size_read(inode1);
 	struct inode		*inode2 = file_inode(fxr->file2);
+	loff_t			size2 = i_size_read(inode2);
 	uint64_t		allocmask = alloc_unit - 1;
 	int64_t			test_len;
 	uint64_t		blen;
-	loff_t			size1, size2, tmp;
+	loff_t			tmp;
 	int			error;
 
 	/* Don't touch certain kinds of inodes */
@@ -337,24 +354,25 @@ xfs_exchange_range_checks(
 	if (IS_SWAPFILE(inode1) || IS_SWAPFILE(inode2))
 		return -ETXTBSY;
 
-	size1 = i_size_read(inode1);
-	size2 = i_size_read(inode2);
-
 	/* Ranges cannot start after EOF. */
 	if (fxr->file1_offset > size1 || fxr->file2_offset > size2)
 		return -EINVAL;
 
-	/*
-	 * If the caller said to exchange to EOF, we set the length of the
-	 * request large enough to cover everything to the end of both files.
-	 */
 	if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) {
+		/*
+		 * If the caller said to exchange to EOF, we set the length of
+		 * the request large enough to cover everything to the end of
+		 * both files.
+		 */
 		fxr->length = max_t(int64_t, size1 - fxr->file1_offset,
 					     size2 - fxr->file2_offset);
-
-		error = xfs_exchange_range_verify_area(fxr);
-		if (error)
-			return error;
+	} else {
+		/*
+		 * Otherwise we require both ranges to end within EOF.
+		 */
+		if (fxr->file1_offset + fxr->length > size1 ||
+		    fxr->file2_offset + fxr->length > size2)
+			return -EINVAL;
 	}
 
 	/*
@@ -371,15 +389,6 @@ xfs_exchange_range_checks(
 		return -EINVAL;
 
 	/*
-	 * We require both ranges to end within EOF, unless we're exchanging
-	 * to EOF.
-	 */
-	if (!(fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF) &&
-	    (fxr->file1_offset + fxr->length > size1 ||
-	     fxr->file2_offset + fxr->length > size2))
-		return -EINVAL;
-
-	/*
 	 * Make sure we don't hit any file size limits.  If we hit any size
 	 * limits such that test_length was adjusted, we abort the whole
 	 * operation.
@@ -607,6 +616,12 @@ xfs_exchrange_prep(
 	if (error || fxr->length == 0)
 		return error;
 
+	if (fxr->flags & __XFS_EXCHANGE_RANGE_CHECK_FRESH2) {
+		error = xfs_exchrange_check_freshness(fxr, ip2);
+		if (error)
+			return error;
+	}
+
 	/* Attach dquots to both inodes before changing block maps. */
 	error = xfs_qm_dqattach(ip2);
 	if (error)
@@ -710,6 +725,7 @@ xfs_exchange_range(
 {
 	struct inode		*inode1 = file_inode(fxr->file1);
 	struct inode		*inode2 = file_inode(fxr->file2);
+	loff_t			check_len = fxr->length;
 	int			ret;
 
 	BUILD_BUG_ON(XFS_EXCHANGE_RANGE_ALL_FLAGS &
@@ -719,7 +735,8 @@ xfs_exchange_range(
 	if (fxr->file1->f_path.mnt != fxr->file2->f_path.mnt)
 		return -EXDEV;
 
-	if (fxr->flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS)
+	if (fxr->flags & ~(XFS_EXCHANGE_RANGE_ALL_FLAGS |
+			 __XFS_EXCHANGE_RANGE_CHECK_FRESH2))
 		return -EINVAL;
 
 	/* Userspace requests only honored for regular files. */
@@ -741,14 +758,18 @@ xfs_exchange_range(
 		return -EBADF;
 
 	/*
-	 * If we're not exchanging to EOF, we can check the areas before
-	 * stabilizing both files' i_size.
+	 * If we're exchanging to EOF we can't calculate the length until taking
+	 * the iolock.  Pass a 0 length to remap_verify_area similar to the
+	 * FICLONE and FICLONERANGE ioctls that support cloning to EOF as well.
 	 */
-	if (!(fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF)) {
-		ret = xfs_exchange_range_verify_area(fxr);
-		if (ret)
-			return ret;
-	}
+	if (fxr->flags & XFS_EXCHANGE_RANGE_TO_EOF)
+		check_len = 0;
+	ret = remap_verify_area(fxr->file1, fxr->file1_offset, check_len, true);
+	if (ret)
+		return ret;
+	ret = remap_verify_area(fxr->file2, fxr->file2_offset, check_len, true);
+	if (ret)
+		return ret;
 
 	/* Update cmtime if the fd/inode don't forbid it. */
 	if (!(fxr->file1->f_mode & FMODE_NOCMTIME) && !IS_NOCMTIME(inode1))
@@ -778,8 +799,6 @@ xfs_ioc_exchange_range(
 		.file2			= file,
 	};
 	struct xfs_exchange_range	args;
-	struct fd			file1;
-	int				error;
 
 	if (copy_from_user(&args, argp, sizeof(args)))
 		return -EFAULT;
@@ -793,12 +812,112 @@ xfs_ioc_exchange_range(
 	fxr.length		= args.length;
 	fxr.flags		= args.flags;
 
-	file1 = fdget(args.file1_fd);
-	if (!file1.file)
+	CLASS(fd, file1)(args.file1_fd);
+	if (fd_empty(file1))
 		return -EBADF;
-	fxr.file1 = file1.file;
+	fxr.file1 = fd_file(file1);
 
-	error = xfs_exchange_range(&fxr);
-	fdput(file1);
-	return error;
+	return xfs_exchange_range(&fxr);
+}
+
+/* Opaque freshness blob for XFS_IOC_COMMIT_RANGE */
+struct xfs_commit_range_fresh {
+	xfs_fsid_t	fsid;		/* m_fixedfsid */
+	__u64		file2_ino;	/* inode number */
+	__s64		file2_mtime;	/* modification time */
+	__s64		file2_ctime;	/* change time */
+	__s32		file2_mtime_nsec; /* mod time, nsec */
+	__s32		file2_ctime_nsec; /* change time, nsec */
+	__u32		file2_gen;	/* inode generation */
+	__u32		magic;		/* zero */
+};
+#define XCR_FRESH_MAGIC	0x444F524B	/* DORK */
+
+/* Set up a commitrange operation by sampling file2's write-related attrs */
+long
+xfs_ioc_start_commit(
+	struct file			*file,
+	struct xfs_commit_range __user	*argp)
+{
+	struct xfs_commit_range		args = { };
+	struct kstat			kstat = { };
+	struct xfs_commit_range_fresh	*kern_f;
+	struct xfs_commit_range_fresh	__user *user_f;
+	struct inode			*inode2 = file_inode(file);
+	struct xfs_inode		*ip2 = XFS_I(inode2);
+	const unsigned int		lockflags = XFS_IOLOCK_SHARED |
+						    XFS_MMAPLOCK_SHARED |
+						    XFS_ILOCK_SHARED;
+
+	BUILD_BUG_ON(sizeof(struct xfs_commit_range_fresh) !=
+		     sizeof(args.file2_freshness));
+
+	kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness;
+
+	memcpy(&kern_f->fsid, ip2->i_mount->m_fixedfsid, sizeof(xfs_fsid_t));
+
+	xfs_ilock(ip2, lockflags);
+	/* Force writing of a distinct ctime if any writes happen. */
+	fill_mg_cmtime(&kstat, STATX_CTIME | STATX_MTIME, inode2);
+	kern_f->file2_ctime		= kstat.ctime.tv_sec;
+	kern_f->file2_ctime_nsec	= kstat.ctime.tv_nsec;
+	kern_f->file2_mtime		= kstat.mtime.tv_sec;
+	kern_f->file2_mtime_nsec	= kstat.mtime.tv_nsec;
+	kern_f->file2_ino		= ip2->i_ino;
+	kern_f->file2_gen		= inode2->i_generation;
+	kern_f->magic			= XCR_FRESH_MAGIC;
+	xfs_iunlock(ip2, lockflags);
+
+	user_f = (struct xfs_commit_range_fresh __user *)&argp->file2_freshness;
+	if (copy_to_user(user_f, kern_f, sizeof(*kern_f)))
+		return -EFAULT;
+
+	return 0;
+}
+
+/*
+ * Exchange file1 and file2 contents if file2 has not been written since the
+ * start commit operation.
+ */
+long
+xfs_ioc_commit_range(
+	struct file			*file,
+	struct xfs_commit_range __user	*argp)
+{
+	struct xfs_exchrange		fxr = {
+		.file2			= file,
+	};
+	struct xfs_commit_range		args;
+	struct xfs_commit_range_fresh	*kern_f;
+	struct xfs_inode		*ip2 = XFS_I(file_inode(file));
+	struct xfs_mount		*mp = ip2->i_mount;
+
+	kern_f = (struct xfs_commit_range_fresh *)&args.file2_freshness;
+
+	if (copy_from_user(&args, argp, sizeof(args)))
+		return -EFAULT;
+	if (args.flags & ~XFS_EXCHANGE_RANGE_ALL_FLAGS)
+		return -EINVAL;
+	if (kern_f->magic != XCR_FRESH_MAGIC)
+		return -EBUSY;
+	if (memcmp(&kern_f->fsid, mp->m_fixedfsid, sizeof(xfs_fsid_t)))
+		return -EBUSY;
+
+	fxr.file1_offset	= args.file1_offset;
+	fxr.file2_offset	= args.file2_offset;
+	fxr.length		= args.length;
+	fxr.flags		= args.flags | __XFS_EXCHANGE_RANGE_CHECK_FRESH2;
+	fxr.file2_ino		= kern_f->file2_ino;
+	fxr.file2_gen		= kern_f->file2_gen;
+	fxr.file2_mtime.tv_sec	= kern_f->file2_mtime;
+	fxr.file2_mtime.tv_nsec	= kern_f->file2_mtime_nsec;
+	fxr.file2_ctime.tv_sec	= kern_f->file2_ctime;
+	fxr.file2_ctime.tv_nsec	= kern_f->file2_ctime_nsec;
+
+	CLASS(fd, file1)(args.file1_fd);
+	if (fd_empty(file1))
+		return -EBADF;
+	fxr.file1 = fd_file(file1);
+
+	return xfs_exchange_range(&fxr);
 }